Overview on power management design

From Openmoko

Contents

State diagram

Normal Mode

Sleep Mode

Poweroff Mode

Slow Mode ??

There has also been discussion (from Cesar) on the kernel list about exploiting the PM suspend and resume driver APIs on a more finegrained basis to tailor consumption to what the device finds itself doing, maybe driven by what dev nodes have handles open on them.

Profile of suspend/resume

Estimate suspend current

System only keeps two power sources, AUTO3v3 and DOWN2 1v8, when it is in suspend. Theoretically, the suspend current should be the sum of the current of all modules which are in sleep/suspend mode connected these two power channels. So we have to know the current consumption of following modules which are in sleep/suspend mode individually.

Glamo

BT

AMP

WLAN

SDRAM

NAND

LCM

Wake-up source

The following modules/events are listed as wake-up sources for GTA02 so far.

GSM

Incoming call:[OK]

SMS:[OK]

The suspend current is about 7mA.

WiFi:[Not verified/implemented]

PMU

Power key:[OK]

RTC(alarm clock):[OK]

USB insert:[OK]

AUX key:This button is used as NOR booting control. It would not enable as wake-up source anymore.

Jackinsert:[OK]

Hold key: There is no requirement to use hold key as wake up source. Now it's eliminated in gta02.

GPIO config

gpio config on A5

gpio config when system get into sleep mode (suspend)

config of glamo in sleep mode

Automated suspend/resume testing

Initial idea is to provide an environment to test suspend/resume process and collect the suspending current.
Basically, we could use multimeter with GPIB to achieve the whole process automatically.